1 Litre no Namida (1リットルの涙, lit. "1 Litre of Tears"; also called A Diary with Tears or A Diary of Tears) is a 2005 Japanese television drama for Fuji TV. It is based on the story of Aya Kitō, who suffered from a degenerative disease and died at the age of 25.

The script is based on Aya's diary that she kept writing in until she could no longer hold a pen. The diary was later titled One Litre of Tears and sold over 1.1 million copies in Japan.